a-low

iTrader: (26)

So I replaced my o2 sensors and fuel filter about 2 months ago and my car was running like a champ, now it hesitatates between shifts (A4). Im getting lousy gas mileage and from 3 -4 gear it backfires loud!!!!! I cleaned the maf just now and added some seafoam to my tank. Oh and Im not showing SES light. Any suggestions?

THE SHOP

How is your basic tune up?

samson_420

iTrader: (1)

Check all the basics. . . Fuel pressure, connections and compression.

a-low

iTrader: (26)

Spark plugs are about a year old, new fuel filter , air filter, car was seafomed yesterday. Havent checked the fuel presurre yet but it did started hapeninig more or less after I replaced my fuel filter.

samson_420

iTrader: (1)

I would check the rest, doesn't sound like a very difficult issue to find.

THE SHOP

Most fuel additives are not really a resolution try to stick with locating a mechanical issue

The02Witchburner

Check the EGR out....have you lost top end or are extremely sluggish on accelleration?

Johnny-LT1-runner

iTrader: (15)

Replace the spark plugs.

YORK_MUSTAINE

iTrader: (2)

Maybe its a exhaust leak on the headers or catback